1. Field of the Invention
The present invention relates to an information recording medium where a data track pattern and a servo pattern are formed by a concave/convex pattern and respective concave parts in the concave/convex pattern are filled with non-magnetic material, a recording/reproducing apparatus equipped with such information recording medium, and a stamper for manufacturing such information recording medium.
2. Description of the Related Art
As one example of a recording/reproducing apparatus equipped with this kind of information recording medium, a magnetic recording apparatus equipped with a discrete track-type magnetic disk is disclosed by Japanese Laid-Open Patent Publication No. H09-97419. The magnetic disk is produced by forming concentric recording tracks (“belt-like convex parts”) composed of a recording magnetic material (“magnetic material”) on one surface side of a glass disc substrate (“substrate”). Guard band parts are also formed by filling spaces (concave parts) between the respective recording tracks with a guard band material (a non-magnetic material) to make the magnetic disk smoother and to magnetically separate adjacent recording tracks. When manufacturing such magnetic disks, first a magnetic material is sputtered onto one surface side of the substrate to form the recording magnetic layer. Next, after a positive-type resist has been spin-coated so as to cover the recording magnetic layer and prebaked, the same pattern as the guard band parts is drawn using a matrix cutting apparatus and then developed. By doing so, a resist pattern is formed on the recording magnetic layer. After this, the recording magnetic layer is etched using the resist pattern as a mask and mask residue is then removed by an ashing apparatus. By doing so, recording tracks and a servo pattern (convex parts) composed of magnetic material are formed on the substrate. After this, a non-magnetic material is sputtered onto the substrate in this state. When doing so, a sufficient amount of non-magnetic material is sputtered until the respective concave parts between the recording tracks are completely filled with the non-magnetic material and the respective recording tracks are covered with the non-magnetic material. Next, the surface of the sputtered non-magnetic material is dry-etched to expose the upper surfaces of the recording tracks from the non-magnetic material. By doing so, recording tracks and guard band parts become adjacent in an alternating manner, thereby completing the magnetic disk.